The present invention relates to a quick-coupling device for fluid circuits that may be subjected to large pressure variations.
Most couplings with toothed washers have teeth that are flexible or resiliently movable and that are attached via their roots to a rigid ring that is housed in a groove of the bore. The groove is generally provided between a shoulder of the bore and an insert, thereby enabling the ring to be embedded and possibly even deformed to modify the angle of inclination of the teeth if the ring does not occupy a radial plane at rest. In other configurations the groove is made entirely in an insert that is pre-fitted with the washer. In order to ensure that the force opposing insertion of the tube is not too great, it is necessary for the teeth to have a degree of flexibility so that they splay apart easily when the end of the tube is passed in through them. This flexibility is obtained by cutouts and recesses in the teeth, but that is to the detriment of their ability to bite into the outer surface of the tube.
In an improvement to that type of coupling, proposals have already been made for a washer that is substantially frustoconical with its inside circumference being of a diameter that is less than the diameter of the tube, and being subdivided into a plurality of teeth, the outer portion of the washer being arranged in a groove formed in the bore, each tooth of the washer being constituted by a rigid blade possessing a short root portion that, at rest, extends in a radial plane, and an active portion that is inclined relative to the radial portion, the washer also including, between successive teeth, an elastically-deformable peripheral connection portion so that deforming the washer as a whole causes its teeth to move without deforming. That solution provides a clear improvement in control over the connection, but its ability to withstand the disconnection force due to the circuit being pressurized remains limited, and insufficient, in particular for circuits in which the fluid is a liquid and in which pressure hammering might occur.
The invention seeks to provide a quick coupling of the type summarized above that includes means for greatly increasing its ability to withstand disconnection. Document U.S. Pat. No. 4,146,254 constitutes the state of the art closest to the invention in that it describes means for radially stiffening retaining teeth so that they bite better into the tube that is to be retained. Nevertheless, that stiffening is not optimum for washers having teeth that are as flexible or as movable as possible in order to avoid impeding insertion of the tubular element. The invention thus proposes an improvement to that state of the art that remedies the above-mentioned drawbacks.